Table of Contents
What is the scientific definition of life?
Life is defined as any system capable of performing functions such as eating, metabolizing, excreting, breathing, moving, growing, reproducing, and responding to external stimuli.
All living organisms store genetic information using the same molecules — DNA and RNA. Written in the genetic code of these molecules is compelling evidence of the shared ancestry of all living things. Some mammalian genes have also been adopted by viruses and later passed onto other mammalian hosts.
Which of the following is not a characteristic of life?
The choice that is not a characteristic of life is C) composed of atoms. All matter is composed of atoms, including every solid, liquid, gas and…
Why are viruses not considered alive?
Viruses are not made out of cells, they can’t keep themselves in a stable state, they don’t grow, and they can’t make their own energy. Even though they definitely replicate and adapt to their environment, viruses are more like androids than real living organisms.
What can the genetic code of an organism reveal?
genetic code, the sequence of nucleotides in deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) that determines the amino acid sequence of proteins. Though the linear sequence of nucleotides in DNA contains the information for protein sequences, proteins are not made directly from DNA.
What is an RNA-based life form?
When considering forms of life based upon ribonucleic acid (RNA), it is clearly important to firstly establish what exactly is meant by “life form” and secondly to ensure that the term “RNA-based” is well defined. On first thought, one might posit that “RNA-based” translates to an organism whose genome consists solely of RNA.
Why is RNA so important for evolution?
RNA offers a logical answer, He said: This molecule can both store genetic information and catalyze reactions, suggesting that early, simple organisms could have relied solely on RNA. “It’s a hybrid,” He said. “So it makes perfect sense as a start.”
What comes first RNA or DNA in life?
“So that implies in life, you have the ribose, the RNA first, and then the DNA comes later,” He said. From that simpler RNA start, more-complex life could arise, evolving the stabler DNA to serve as a long-term library and developing protein as a more efficient catalyst.
Why is RNA more flexible than DNA?
RNA’s greater flexibility over DNA comes in part from the extra oxygen on RNA’s ribose sugar, which makes the molecule less stable, biologist Merlin Crossley wrote in The Conversation. The “deoxy” in deoxyribose references DNA’s 1-oxygen deficit.